The present invention relates to a heavy-duty tire, more particularly to a tread pattern suitable for truck/bus tires capable of controlling uneven wear at the edges of a circumferential rib.
A heavy-duty tire for subway cars and monorail cars having tread blocks and zigzag circumferential grooves axially dividing the tread blocks is disclosed in Japanese patent application publication No. 8-192607, wherein in order to reduce uneven wear of the tread, sipes are provided on both sides of the zigzag circumferential grooves, and the positions of the sipes are protruding portions of the zigzag groove walls.
In the case of heavy-duty tires for trucks and buses, in comparison with the tires for subway cars and monorail cars, the traveling conditions are widely and largely varies in use. Therefore, even if sipes are disposed at the protruding portions of the zigzag groove walls, uneven wear occurring on both sides of a circumferential groove can not be prevented.